Semiconductor device having lead frame with notched inner leads

Abstract

A semiconductor device is assembled from a lead frame. The device has a semiconductor die mounted on a flag of the lead frame. A mold compound forms a housing that covers the die. Lead fingers surround the die. Each lead finger has an inner lead length that is covered by the housing and an outer lead length that protrudes from the housing. The inner lead length extends from an edge of the housing towards the die. The inner lead length has an intermediate region that has been bent to form a notch. Bond wires electrically connect electrodes of the die to respective inner lead lengths.

The invention claimed is: 
     
       1. A lead frame sheet with an array of lead frames formed therein, each of the lead frames comprising:
 a die flag surrounded by a frame; 
 tie bars extending inwardly from the frame and supporting the die flag; 
 dam bars defining an external package housing outline, wherein each of the dam bars is supported by the surrounding frame; and 
 lead fingers each having an inner lead length extending from one of the dam bars towards the die mount and an outer lead length extending from said one of the dam bars away from the die mount and towards the outer frame, 
 wherein the inner lead length has an intermediate region that has been bent to form a notch, wherein the notch includes two straight sloping walls meeting at an apex of the notch. 
 
     
     
       2. The lead frame sheet of  claim 1 , wherein the straight sloping walls extend above an upper surface of the inner lead length. 
     
     
       3. The lead frame sheet of  claim 1 , wherein the straight sloping walls extend below a lower surface of the inner lead length. 
     
     
       4. The lead frame sheet of  claim 1 , wherein the inner lead length either side of the notch is coplanar. 
     
     
       5. A semiconductor die package, comprising:
 a semiconductor die mounted on a die flag; 
 a mold compound forming a housing that covers the semiconductor die; 
 lead fingers each having an inner lead length covered by the housing and an outer lead length protruding from the housing, wherein the inner lead lengths extend from an edge of the housing towards the die flag, and wherein the inner lead lengths have an intermediate region having a bend that forms a notch, wherein the notch includes two straight sloping walls meeting at an apex of the notch, and wherein the notch is covered by the mold compound; and 
 bond wires electrically connecting electrodes of the semiconductor die to the inner lead lengths. 
 
     
     
       6. The semiconductor die package of  claim 5 , wherein the straight sloping walls extend above an upper surface of the inner lead length. 
     
     
       7. The semiconductor die package of  claim 5 , wherein the straight sloping walls extend below a lower surface of the inner lead length. 
     
     
       8. The semiconductor die package of  claim 5 , wherein the inner lead length either side of the notch is coplanar.